<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
        html{
            height: 100%;
        }
        body{
            height: 100%;
        }
        .item1{
            background-color: rgb(172, 244, 182);
        }
        .item2{
            background-color: rgb(255, 233, 117);
        }
        .item3{
            background-color: rgb(94, 255, 250);
        }
        .item4{
            background-color: rgb(230, 180, 253);
        }
        .item5{
            background-color: rgb(141, 254, 205);
        }
        .item6{
            background-color: rgb(253, 154, 92);
        }
        .wrapper{
            display: grid;
            height: 100%;
            grid-template-columns: 33.3% 33.3% 33.3%;
            grid-template-rows: 50px 50px;
        }
        
    </style>
</head>
<body>
    <div class="wrapper">
        <div class="item1">1</div>
        <div class="item2">2</div>
        <div class="item3">3</div>
        <div class="item4">4</div>
        <div class="item5">5</div>
        <div class="item6">6</div>    
    </div>
</body>
</html>